Persistent low ammonia spike

[dmaccy]

Hi. I have a tank which has been set up for 9 months and has been stable.
However I went away for a couple of weeks and came back to a tabk with high ammonia and two dead fish. Note that whilst I was away a friend did a water change for me so no change to normal routine.i have also spoke to said friend who explained they didn't do any of the normal errors, e.g. tap water sponge clean). I'd also doubt an ammonia bubble was released from the sand ( although possible but unlikely)

Whilst I removed one of the dead fish I have yet to find the other. I have removed all tank decor, emptied and cleaned both filters and I have even removed and replanted all the plants and no sign of the fish.

This was about 3 weeks ago and the ammonia has yet to return to zero. I am water changing every other day or so and the ammonia reading is persistently between 0.2 and 0.5 ppm. I'm also slightly confused as the Nitrites are consistently reading zero ( or at least too low to be visible to the naked eye using nt labs liquid test).

Two questions:
Can anyone share any other places where a dead fish may have lodged itself?
Has anyone else had a spike last a few weeks in an established tank?


Please fire away with questions for any more info or hypotheses to test.

 

[TwoTankAmin]

This will be a bit long, but it should explain what your are seeing. However, I am writing this as much for other as for you because at the very end I will give you the most important consideration here.

There are a few things that can cause ammonia reading which are not ammonia. Also, the ammonia tests can give false readings. What you report is a classical case of not being accurate readings. here is how you can recognize them.

The first clue is no nitrite. In a cycled tank the two types of bacteria are in balance so as fast as the ammonia is created the nitrite is also converted. But most of the things that can kill off or retard one will also do so for the other. Unless one is at the start of the cycle, you should not read ammonia for very long before you get a nitrite reading. Your lack of nitrite is a clue to the fact there may not really be excess ammonia.

Next, whenever you test you see .2 - .5 ppm. These two colors are pretty close and you may actually have a narrower range then your subjective vision can discern. But lets do an exrecise here which will illustrate the point. I am gonig to give you a tank with substrate and a filter with good biomedia. I am going to give you natural water with no chlorine, chloramine or ammonia. I am also going to give you an accurate way to does a specific amount off ammonia into that many gallons. Your job is to keep that tank at a steady reading of 0.375 ppm ammonia reading. You can change water of add ammonia as needed.

Now here is the fun part. I am going yo show up at your place at random times on random days with a highly accurate digital ammonia tester and an equally good one for nitrite. You job is to do what ever it takes to insure when I arrive and test I always get a reading at 0.375 ppm +/- 0.125 ppm of ammonia and 0 for nitrite.

Tell me how you are going to do this? The answer is the only way is to have a small lab with and automatic doser and a high speed water changer and very accurate digital testing equipment to achive a constant concentration. Here is why you will not be able to do what I have descirbed. And even this wont work as emptying and filling the tank and getting the right amount of ammonia in takes time. I may come to test before you can have things reset.

As you begin to add the ammonia, you will also begin to get the few ammonia bacteria that arrived with the water and.or from the air. They will begin to multipy. As they do they will be using the added ammonia which means to keep a comnstant concentration ammonia additions must added more frequently at the start and then in increasing amounts later on. Very soon you will have nitrite. While you can prevent ntrite from entering a fish using salt, this does not remove it from the water. Only water changes will do this, but they wont work for long.

Sooner or later I will come to test and the ammoin readins qill be out of the range or else there will be nitrite. Now take this down to the less accurate liquid test kits we use in the hobby and you should see how easy it is to get a false reading. But there are some things we do have in our tank water than can give a false ammonia reading, Iron is one such thing.

Even if you have ammonia in your incoming tap water and your dechlor does not detoxify ammonia, you should still see this work like a cycle and you will see the ammonia rise than drop to zera and you will see nitrite as well.

Finally, claning the substarte and the filter media can acti to reduce nacteria. As much of it iis usally in the top 1/2 inch of substrate as in the filter media. And if you have live plants with roots in the substrate they likely tansport oxygen down to and out of their roots to encourage nitrifying bacteria in the anaerobic zone around them and this is normally followed by zones of denitrification above and below.

I would bett ny dollars against your dead fish that the ammonia reading you are now seeing is not real, especially if there are no ammonia sources (fish etc.) in the tank. bear in mind that ammonia is a gas and will evaporate from water as the water evaporates. The warmer the water and the more surface aggitation there is, the faster the ammonia will evaporate. This another reason why it is almost impossible to keep a constant concentration of ammonia in tank water.

So i am again saying that your ammonia readins are not accurate as reported. This doesn't mean you are testing wrong, your kits is expired or even that it is seeing something it thinks is ammonia. However, it is not ammonia. However, this does not mean you did not have an
ammonia spike.

Now for the kicker I promised. Live plants use ammonia and they do so more effriciently and much faster than the bacteria. Most live plants arrive with live bacteria on them. the reason is basic chemistry. Ammonia is a gas (NH3_) but dissolved in water most of it turns to ammoniaum (NH4). the plants prefer ammonium and the bacteria prefer ammonia. So, when both are present in a tank and you have live plants, you also have bacteria. However, in a tank woth no plants, you will have all bacteria handling the ammonia. Thus there is more bacteria neede in an unplanted v.s. a planted tank with similar ammonia loads. Plants make it even more impossible to have a constant level of ammonia in a tank.

 

[Colin_T]

Have you checked and cleaned the filter?
A dead fish, or parts of one might be stuck in the filter.

How much water do you change?

Have you checked the tap water for ammonia, nitrite, nitrate and pH?
Water companies sometimes add too much ammonia to the tap water when they make chloramine and you can add free ammonia to a tank if this has happened.

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I would check the tap water and if it's good (0 ammonia, 0 nitrite, 0 nitrate), then do a 75% water change and gravel clean the substrate every day for a week. I would also clean the filter if it hasn't been done in the last 2 weeks, just to make sure it's clean and free of things that rot.
Maker sure any new water is free of chlorine/ chloramine before it's added to the tank.

If you still get an ammonia reading after that, take a sample of tank water to a pet shop and get them to test it. Take your own test kit with you and test the same sample at the same time. Compare the results. If your kit gives a reading but the shops doesn't, then you might have a faulty test kit.

Make sure you wash the test phials out under running water after each use.

Keep test kits cool, dry and out of light when not being used because heat, humidity and bright light destroy the reagents in the test solutions.

 

[TwoTankAmin]

If there is something dead and decaying the ammonia would not stay that constant, The size of the material rotting is changing as is the rate of overall decay. Ammonia numbers should move over time more than indicated. You could not [produce then intentianally and neither should nature.

Next plants use ammonia so they should be using some of it and that should cause them to grow. Bigger plants take up more ammonia. This should also have an effect on ammonia readings.

Then there re the bacteria, they reproduce when there is more ammonia and/or nitirte than they need to thrive. This is why a tank cycles. If the ammonia reading is real, then one of two things have to happen. Either the bacteria multiply and the ammonia and then nitrite will drop to 0 or else the ammonia and nitrite will accumulate and the numbers have to rise. Staying fairly constant over time is not an option.

Throw in water changes as reported and the chances of creating such a persistent low reading over time is almost impossible. So if we rule out the impossible, what should remain is the possible. And that is something in the water causing a false reading and/or something wrong with testing are the most likely culprits.

Even if there is ammonia in the tap the, tank should read the highest level of ammonia right after the water change vs. right before the next water change. Maybe you could come close if the tap has a steady level of ammponia and you change a lot of water daily or close to it. And then if there is always actual ammonia in the tank there also has to be nitrite as well. The nitrite bacteria reproduce more slowly. So if more ammonia is being turned to nitrite there will be a lag and you will read nitrite when you test for it.

Now there is one more kicker to all of this. The bacteria in tanks that convert the nitrite to nitrate are Nitrospira. A few years back it was discoverd they they are actually able to convert ammonia to nitrate. This may explain one reason for the low amount of the ammonia oxidizers numbers normally found as a percent of the toal bacteria incolved. And this also means it should be even more impossible to keep a steady reading of ammonia in a tank for any length of time.

 

[itiwhetu]

A photo of the tank please? Do you have live plants and what fish are in the tank? How do you feed this tank, how much, how often?

 

[dmaccy]

Thanks all. To answer the questions asked I have tested the tap water and it showing some ammonia but less than 0.2ppm. Interestingly the tanks test today was also less than 0.2ppm. I have also used two test kits. Primarily the nt labs but i have also double checked with the tetra kit a couple of times too.

Also I have two filters , one internal and one external and I've emptied and cleaned both a couple of times .

 

[Colin_T]

You have chloramine in the water supply and the water company put too much ammonia in the water.

 

[dmaccy]

You have chloramine in the water supply and the water company put too much ammonia in the water.

What's the best thing to do ?.

 

[Colin_T]

You can contact the water company and let them know they have added too much ammonia to the drinking water.

A small amount of ammonia (0.2ppm) in the tap water should be removed by the filter bacteria pretty quickly (within an hour). If you use a water conditioner that is designed to deal with chloramine, it should bind to or convert the ammonia into a less harmful form (ammonium), and the filter should be able to remove it.

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You might have had a power failure at your house while you were away. If the filter bacteria died off due to a power failure, the tank could be going through a filter cycle again.

I would reduce feeding and monitor the fish and ammonia, nitrite and nitrate over the next few weeks.

You could try adding some liquid filter bacteria supplement (available from most pet shops or online). Add a double dose each day for a week and then pour the remaining contents into the tank. try to add the bacteria near the filter intake so it gets drawn into the filter where t belongs.

Adding some floating plants like Water Sprite (Ceratopteris thalictroides/ cornuta) might help too. Floating plants use up ammonia and can help keep levels low or at 0ppm.

 

[gilpi]

You mentioned you emptied and cleaned the filters? What exactly do you mean? Cleaning filters is something that can deplete your beneficial bacteria since this is where it resides and the cycle takes place. The filter media should never be changed only slightly rinsed in some aquarium water.

 

[TwoTankAmin]

The thing about the nitrifying bacteria is that they are mostle immobile inside a bio-film. The bacteria do not go out hunting for their "food" it must come to them. Some small number of them will be motile wich lets them spread or move to new places. The bacteria also are somewhat photophobic and tend to want to be out of the light.

So where do they actually live in a tank? The answer is basically quite simple, they live in the greatest numbers where they can get the most of what they need. This is often, but not always or exclusively in filter media. They need things they take from the water including oxygen. Finally, when we talk about the bacteria we are not discussing individuals but colonies containing large numbers. Some of the places in tanks where one can fidn a lot of the bacteria: in a filter, in the top 1/2 inch of so of the substrate, on the roots, stems and leaves of aquatic plants, on the glass, on the decor. basically, anywhere they can get a good supply of what they need delivered to them, they colonize and multiply.

What does this mean when we are doing tank maint. in an established tank. If you do a decent rinse of the filter media, some bacteria will be lost. As a result there wil be more ammonia than the remaining bacteria need to thrive and they will respond by reproducing. As an example here a simple explanation that is not realizitic in terms of the numbers.

Lets assume that we have an established tank which contains 1,000 bacterial cells. 400 are in the filter, 400 are in the subsstrate and 200 are scatterered around the tank on the underside of decor etc. Now we rinse out the media in the filter and we are overly zealous and we rinse away 200 cells or 20% of the total in the tank and 1/2 of what was in the filter. In response to more ammonia becoming available, the other 80% will start to reproduce. And when they are back up to strength in pretty rapid oreder, we may find that there are 350 in filter, 500 in the substrate and 154 on ther decor. The next week we do a deep vac. but do not need to clean filter media. And again we lose 200 bacteria but this time they were all in the substrate. And again reproduction starts and when back to 100% we now have 450 in the filter, 400 in the substrate and 150 on the decor.

As you can see where the individuals live in the greatest numbers can change but the total tends to remain constant as long as the same applies to ammonia being created in the tank. Now all of this can change simply because we alter the circulation in a tank. The point is that the bacteria will thrive best where conditions are the best for them to do so. Moreover, how we care for a tank can change where the bacteria are.

Finally, the bacteria are not moving from one location to the other to change where the are most concentrated. This process is actually a function of reproduction. Every day individual bacteria are dying for any number of reasons. At the same time, some number are dividing. So the effect is the total coloniy size stays frairly constant, but the where the highest concentration of individuals are can change. The bacteria are not moving from one location to the other, they are just reproducing and dying off at different rates in various locations. What controls it all is where they can best get what they need to thrive and reproduce.